Method of making light metal alloys



PatentedNov. 11, 192 4. x

oFFicE.

WILLIAM R. VEAZEY, F CLEVELAND, OHIO, ASSIGNOR TO THE DOW CHEMICALCOMPANY, OF. MIDLAND, MICHIGAN, A CORPORATION OF MICHIGAN.

METHOD OF MAKING:

provement in Methods of Making Light Metal Alloys, of which thefollowing is a specification, the principle of the invention belngherein explained andthe best mode in which I have contemplated applyingthat principle, so as to distinguish it from other inventions.

The present improved alloy relates to the class in which magnesium isthe predominant metal, so that the term light metal alloy may beappropriately applied thereto. The alloying metal in the present, caseis beryllium, (or glucinum as it is also called) and the inventioninvolves not only the product consisting of. an admixture of the twometals in question in varying proportions, but also in the steps formaking such alloy, all as hereinafter fully described and pointed out inthe claims. The following description, it will be understood, thus setsforth but several of the various ways in which the invention may becarried out.

It is recognized that metallic beryllium is very diflicult to obtain;accordingly I do not attempt to obtain such metal in isolated form foruse in preparing my improved al 10y, but rely on the reducing action ofmetallic magnesium on available compounds of beryllium. By properproportioning of the amounts of magnesium and such beryllium compound,and by properly controlling the rate of reaction, the metallic berylliumas formed will go into solution in the magnesium, or vice versa, so thatthe beryllium does not require to be segregated at all. Magnesium metalis of course available, being commercially manufactured on an increasingscale from year to year.

As already indicated, my improved method of making an alloy of berylliumand magnesium, briefly stated, consists in admixing, while in moltencondition, a suitable quantity of a mixture of halide of beryllium andanother metalland'metallic magnesium. 'ihe most readily availablecompound of beryllium is the double fluoride with the sodium, (BeF, 2NaFor BeF NaF). Other halogen salts of beryllium may be used, but not assatisfactorily.

I have found the preferred method of pro- LIG-HT METAL ALLOYS.

1920. Serial No. 379,803.

cedure to be, first to melt metallic magnesium in asuitable, e. g. iron,crucible, under a flux consisting of a mixture of magnesi um and sodiumchlorides in order to prevent burning; then' the double fluoride referred to above is added in such amounts and at such intervals as willprevent the resultmg reaction from becoming too violent. The moltenmagnesium, in' other words, reacts almost instantly with the berylliumfluoride, beryllium with corresponding formation of magnesium fluoride.The latter with the sodium fluoride form additions to the flux while themetallic beryllium goes directly into solution with the molten magnesiumforming an alloy therewith. So far as I have been able to determine thereaction in' question may be continued by adding more of the doublefiuorideso as to secure any desired proportion of beryllium to magnesiumin the residual metallic mass. The

amount of magnesium required is of course in excess of that present inthe finalalloy by an amount at least equal to that required to reducethe beryllium in such final p'r0d uct. I

Instead of adding the double fluoride of beryllium and sodium to moltenmagnesium I have found it entirely feasible to reverse the process byadding metallic magnesium to such fluoride, the latter being in moltenstate. In other words, I fuse a quantity of beryllium'sodium fluoride inan iron vessel and then add pieces of magnesium thereto, such piecesbeing of a size, and added at such a rate, as to permit effectivecontrol of the reaction as before. Presumably magnesium fluoride isformed and metallic beryllium, the sodium fluoride remaining andforming, with the magnesium fluorlde, a thick pasty mass, out of whichultimately collects the molten alloy in which the proportionof berylliumto magnesium is determined as before.

I have succeeded in making alloys of the metals in question by themethods just described containing as high as 16 per cent of beryllium,so far as can be determined b available methods of analysis. It shouldbe explained that not only is it extremely difiicult accurately todetermine the percentage of beryllium, but, as is well known, thequantitative determination of magnesium even in well-known alloys, suchas those formed with a'liu'minum, is a matter of extreme difliculty,with a corresponding degree of uncertainty in the result. 1

One of the striking characteristics of the alloy in question which Ihave noted incidentally to the production of the same by the generalprocess just described is that such alloy tends to stick to the surfaceof the iron vessel in which the fusion is conducted. In other words,whereas magnesium by itself will not adhere to iron so as to coat thesame, by mixing even a small amount of beryllium therewith thisdifficulty is overcome, and a firm and apparently permanent bond securedbetween the two met als. The importance of this discovery, where it isdesired to provide an iron wearing surface forarticles composed chieflyof magnesium will be readily understood.

Other modes of applying the principle of my invention may be employedinstead of the one explained, change being made as regards the methodherein disclosed provided the step or steps stated by any of thefollowing claims or the equivalent of such statedstep or steps beemployed. I therefore particularly point out and distinctly claim as myinvention '1. The method of causing magnes um to adhere to iron, whichconsists in applying an admixture of beryllium with such mag nesiumwhile in molten statein contact with the iron article to be coated.

2. The method of making an alloy of beryllium and magnesium, whichconsists in admixing while in molten condition a suitable quantity of amixed halide of beryllium and another metal, the halide of which is notreduced by magnesium, and metallic magnesium. D

3. The method of making an alloy of beryllium and magnesium, whichconsists in admixing While in molten condition a suit able quantity of adouble fluoride ofberyladding to molten magnesium a mixed halide ofberyllium and another metal, the halide of which is not reduced bymagnesium.

6. The method of making an alloy of beryllium and magnesium, whichconsists in adding a double fluoride of beryllium and an alkali metal tomolten magnesium.

7. The method of making an alloy of be ryllium and magnesium,whichconsists in adding a double fluoride of beryllium and sodium to moltenmagnesium.

8. In a method of makingan alloy of beryllium and magnesium, the stepswhich consists in melting a quantity of magnesium under a suitable fluxand then gradually adding a double fluoride of beryllium and another'metal producing'a compound not reduced by magnesium until the desiredproportion of such beryllium is secured.

Signed by me, this 6th day of May, 1920.

WILLIAM R. VEAIZIEY.

